Gas discharge devices of the plasma panel type are known in the prior art which include a gas filled gas-tight enclosure having therein a front plate, a rear plate and a plate shaped control structure which sub-divides the interior of the enclosure into two chambers. See, for example, U.S. Pat. No. 4,112,329, assigned to the same assignee as the present invention. The control structure of this disclosure is a plate like matrix which has formed on an insulating plate on its two sides electrode paths which are separately actuatable and which are formed as rows and column conductors of a matrix. The control structure, together with these paths is perforated at the intersection points of the matrix. There is at least one plasma electrode (preferably a plate cathode running parallel to the control structure) in the gas discharge chamber of the enclosure, and there is also at least one post acceleration anode in the other enclosure chamber. A plasma electrode is arranged in such a manner that ignition in the gas discharge space may be brought about. The post acceleration electrode is kept, by means of spacing elements, at a minimal distance, relative to the electron paths, facing the post acceleration anode, of the control structure. Plasma panels are disclosed in the prior art in several variations. See, for example, German Auslegeschrift No. 1,811,272, German Offenlegungsschrift No. 2,412,869, U.S. Pat. No. 3,800,186, U.S. Pat. No. 3,845,241 and U.S. Pat. No. 4,112,329. These prior art disclosures operate according to the following principle. The plasma produced in the discharge space serves as the electron source. From this source, electrons are drawn into a post acceleration space by means of selectively actuating apertures in the control structure. There they consume energies of several kV, and finally impinge on the post acceleration anode, whereby a luminescent spot results in a luminescent layer placed in front of the anode. This light spot is particularly bright if the glow discharge according to German OS No. 2,412,869 burns in the form of a wedge-shaped longitudinal plasma between a plate cathode running parallel to a control plate and the respective activated rows of the control plate.
In the described dual chamber displays, primarily when they operate with a prismatic longitudinal discharge, what is of major importance is that the control structure maintain, over its entire surface a constant spacing of approximately 1 mm, relative to the post acceleration anode. Only then are the potential conditions provided that the anode penetration is identical at all openings of the control structure which enables the displays to be switched in a clean fashion at every image point with relatively low voltage.
The necessary spacing theoretically could be realized with a plate which is inserted between the front plate and the control structure and which contains holes which are in alignment with the control structure openings. However, practice has shown that such a plate, which still must be thicker than the control structure by a multiple thereof, cannot readily be provided with a plurality of fine perforations, and, accordingly, virtually does not enter into consideration, e.g., for a television picture screen.
For this reason, it has already been considered to suspend the control plate from the rear plate via small rods, or space said control plate relative to the front plate by means of pins, to mutually support against one another the two exterior plates by means of comb-like plates penetrating the control structure at individual locations (see U.S. Pat. No. 4,112,329, assigned to the same assignee as the present invention). Rod- or pin-technology, respectively, may achieve its purpose in the case of control structures with a plate-shaped electrode carrier; however, it is less suitable in the case of control units comprising an electrode substrate spaced between the row conductors (U.S. Pat. No. 4,112,329). In the case of structures with a covered carrier, it would be possible to change over to the supportplate variant; however, the assembly of the display does not work out very simply, and, in addition, a danger exists that the very thin prongs or tines may, under certain circumstances, yield to buckling.